Kirk,
I haven't checked in here much lately, but I read your thread and request.
A few thoughts from me on the subject...
I think your plan looks pretty good, but....during those last 12 months of mopping floors, cleaning crappers and digging chips out of dark, long- neglected places in machine tools and fixing said machines, have them also doing some bookwork. Blueprint reading. Shop Math. Measuring instruments and fundamentals. GD&T Dimensioning Pneumatic fundamentals Hydraulic fundamentals Make them take the Sandvik home study course on machining (Very valuable information in that, and they get a certificate when completed, and it's at NO COST unless you don't complete the course.) Basic CNC programming. Create a program on basic CNC/machine operation. (How the machine actually works. - Logic and what not.)
They will be much more prepared for making that decision as to what is to follow the 18 month gig. As a bonus, everything I've listed above will be of huge benefit no matter which of the 3 splits they take.
Another thing to remember...when teaching... Never, EVER, give the answer... Always make them deduce the answer of their own. You do this by asking a series of leading questions that steer them to the correct answer, but you never actually give it until they come up with it on their own..